This sets whether users can use compilers or not. If they are disabled from using a compiler, then the C compiler won't work to install perl modules in cPanel. Your host would simply need to enable compiler access, or they should remove the option to install perl modules in cPanel for accounts.

I'm having the same problem unfortunately, after upgrading cpanel. I came across it after trying to fix the broken language files in cpanel. Google only takes me here and one other page when researching this broken C compiler.

I fixed this on a server recently due to /root/tmp/ being a symlink to /tmp/. /tmp/ is set noexec (which may or may not matter), but when I removed the symlink from /root/tmp to /tmp, then did mkdir /root/tmp/ to leave a 755 root:root dir there, the "working C compiler" error went away

Your error said it couldn't locate a gcc binary; I know this is an old post, but you'd want to run 'which gcc' and see if it returns something like /usr/bin/gcc. If it doesn't, you've got some bigger problems, and should use your package manager to re-install gcc. I did this on a centOS system with RPM/YUM by doing: